! Hubble Space Telescope Cycle 5 (1995) Phase II Proposal Template
! $Id: 5814,v 1.1 1994/12/14 19:46:28 pepsa Exp $
!
!   Refer to the HST Phase II Proposal Instructions to fill this out
!
!   Anything after a "!" is ignored, and may be deleted
!
!   All keywords with multiple entries are comma delimited except the
!   Visit_Requirements and Special_Requirements keywords which can be
!   delimited with carriage returns or semi-colons, but not commas
!
! For help call your Program Coordinator: n/a
!             Phone: n/a             , E-mail: n/a
!
! This partially completed template was generated from a Phase I proposal.
! Name of Phase I Proposal: turnshek-702.prop
! Date generated: Wed Dec 14 14:46:21 EST 1994
!

Proposal_Information                           ! Section 4
              Title:  The Optical Depth of the Diffuse
                      Intergalactic Medium
  Proposal_Category:  AR
Scientific_Category:  Quasars
             Cycle:    5

Investigators
     PI_name:         David Turnshek
     PI_Institution:  Dept. of Physics & Astronomy,   \ University
                      of Pittsburgh

          CoI_Name:   Valery Khersonsky
   CoI_Institution:   Dept. of Physics & Astronomy,, University of
                      Pittsburgh
           Contact:             ! Y or N (designate at most one contact)


Abstract:                                ! Free format text (please update)
    -0.1 truein The diffuse intergalactic medium may give rise to
    weak absorption troughs in the spectra of background quasars,
    i.e., the so-called Gunn-Peterson effect. The goal of this
    program is to assemble suitable UV archival HST-FOS spectra of
    quasars for study of the Gunn-Peterson effect in the
    HILambda1216 and HeILambda584 LyAlpha lines.  By fitting
    quasar spectral energy distributions and extrapolating to
    regions of interest, we will measure or place upper limits on
    diffuse HILambda1216 absorption at redshifts z < 0.9 and
    diffuse HeILambda584 at redshifts 1.1 < z < 2.7.  Archival
    measurements can be made for as many as 46 ideal objects in
    the case of HILambda1216 and 14 objects in the case of
    HeILambda584.  We expect our measurements to establish upper
    limits or evidence for weak absorption.  The measurements will
    be:  (1) the best limits that can be derived, (2) significant
    for models, and (3) complementary to ongoing HST searches for
    diffuse HeIILambda304 absorption at z > 2.8. Constraints on
    the Gunn-Peterson effect in the absorption spectra of quasars
    provide information on the diffuse UV ionizing radiation,
    which is thought to be mostly generated by quasars and young
    star-burst galaxies, and on the processes of galaxy and
    structure formation in the Universe.  Some models for the
    strength of the Gunn-Peterson absorption troughs predict
    optical depths as high as Tau ~ 0.1.  However, the theoretical
    predictions are very sensitive to several model parameters
    which are largely unknown.  Direct measurements of the Gunn-
    Peterson effect at these redshifts are therefore very
    worthwhile.

Questions                       ! Free format text (please update)

     Observing_Description:

   Real_Time_Justification:



Calibration_Justification:              ! Move appropriate text from Real_Time_Justification

      Additional_Comments:


Fixed_Targets                           ! Section 5.1
  Target_Number:
    Target_Name:
Alternate_Names:
    Description:
       Position:                        ! Most common specification format is
                                        ! RA=0H 0M 0.00S +/- 0S,
                                        ! DEC=0D 0' 0.0" +/- 0",
                                        ! PLATE-ID=0000
        Equinox:
        RV_or_Z:
          RA_PM:                        ! Units are seconds of time per year
         Dec_PM:                        ! Units are seconds of arc per year
          Epoch:
Annual_Parallax:
           Flux:                        ! Include at least V and B-V
       Comments:


Solar_System_Targets                    ! Section 5.2
  Target_Number:
    Target_Name:
    Description:
        Level_1:                        ! Satellite of Sun
        Level_2:                        ! Satellite of Level_1
        Level_3:                        ! Satellite of Level_2
         Window:
           Flux:                        ! Include at least V and B-V
       Comments:


Generic_Targets                         ! Section 5.3
  Target_Number:
    Target_Name:
    Description:
       Criteria:
           Flux:
       Comments:


Scan_Data                               ! Appendix B
    Scan_Number:
       FGS_Scan:
  Cont_or_Dwell:
   Dwell_Points:
     Dwell_Secs:
     Scan_Width:
    Scan_Length:
    Sides_Angle:
   Number_Lines:
      Scan_Rate:
  First_Line_PA:
     Scan_Frame:
  Length_Offset:
   Width_Offset:


! This is a template for a single visit containing a single exposure
! Repeat exposure and visit blocks as needed

Visits                                  ! Section 6
      Visit_Number:
Visit_Requirements:                     ! Section 7.1

! Uncomment or copy visit level special requirements needed
! Most of these requirements (including ORIENT) will limit scheduling

        ! PCS MODE [Fine | Gyro]
        ! GUIDing TOLerance <angle>
        ! ORIENTation <angle1> TO <angle2>
        ! ORIENTation <angle1> TO <angle2> FROM <visit>
        ! ORIENTation <angle1> TO <angle2> FROM NOMINAL
        ! SAME ORIENTation AS <visit>
        ! CVZ
        ! PARallel
        ! AFTER <visit> [BY <time1> [TO <time2>]]
        ! AFTER <date>
        ! BEFORE <date>
        ! BETWEEN <date1> AND <date2>
        ! GROUP <visit-list> WITHIN <time>
        ! PERIOD <time> AND ZERO-PHASE <date>
        ! SEQ <visit-list> WITHIN <time>
        ! ON HOLD [FOR <visit>]

  On_Hold_Comments:
    Visit_Comments:

     Exposure_Number:                   ! Section 6.5
         Target_Name:
              Config:
              Opmode:
            Aperture:
          Sp_Element:
          Wavelength:
 Optional_Parameters:
Number_of_Iterations:
   Time_Per_Exposure:
Special_Requirements:                   ! Section 7.2

! Uncomment or copy exposure level special requirements needed

        ! INTeractive ACQuisition FOR <exp-list>
        ! ONBOARD ACQuisition FOR <exp-list>
        ! POSition TARGet <x-value>,<y-value>
        ! SAME POSition AS <exp>
        ! DO FOR TARGets <targ-list>    ! FGS only
        ! PARallel WITH <exp>
        ! GROUP-FGS <exp-list> WITHIN <time>
        ! SPATIAL SCAN <#> [<exp-list> | SINGLE-EXP ]
        ! RT ANALYSIS [FOR <exp-list>]
        ! REQuires UPLINK
        ! DARK TIME
        ! END ORBIT
        ! EXPAND
        ! MAXimum DURation [<time> | <%>]
        ! MINimum DURation [<time> | <%>]
        ! NO SPLIT
        ! PHASE <number1[0,1]> TO <number2[0,1]>
        ! SEQuence <exp-list> NON-INTerruptible

            Comments:

Data_Distribution                       ! Defaults indicated; change if desired

         Medium:        8MM             ! 8MM or 6250BPI or 1600BPI
Blocking_Factor:        10              ! 10 or 1
                                        ! Only astronomers with very old 9-
                                        ! track tape drives should consider
                                        ! a blocking factor of 1

        Ship_To:        PI_Address      ! STSCI or PI_Address or <free-text>
                                        ! PI Address from Phase I is:
                                        !
                                                 !  Pittsburgh, PA 15260
                                        !
                                        !
       Ship_Via:        UPS             ! UPS (2-day) or OVERNIGHT
                                        ! Overnight shipping done at PI expense

Recipient_Email:                        ! Needed if Ship_To: is not PI_Address
                                        ! <free-text>

! Let us know what you think of this template and software!
! Please send a list of your likes and dislikes to your Program Coordinator